keyforkd{,-client}: lots of documentationings

crates/daemon/keyforkd-client/src/lib.rs

@@ -1,8 +1,10 @@
 //! # The Keyforkd Client
 //!
 //! Keyfork allows securing the master key and highest-level derivation keys by having derivation
-//! requests performed against a server, "Keyforkd" or the "Keyfork Server". The server is operated
+//! requests performed against a server, "Keyforkd" or the "Keyfork Server". This allows
-//! on a UNIX socket with messages sent using the Keyfork Frame format.
+//! enforcement of policies, such as requiring at least two leves of a derivation path (for
+//! instance, `m/0'` would not be allowed, but `m/0'/0'` would). The server is operated on a UNIX
+//! socket with messages sent using the Keyfork Frame format.
 //!
 //! Programs using the Keyfork Client should ensure they are built against a compatible version of
 //! the Keyfork Server. For versions prior to `1.0.0`, all versions within a "minor" version (i.e.,
@@ -10,18 +12,23 @@
 //! after `1.0.0`, all versions within a "major" version (i.e., `1.0.0`) will be compatible, but
 //! `1.x.y` will not be compatible with `2.0.0`.
 //!
-//! Presently, the Keyfork server only supports the following requests:
+//! The Keyfork Client documentation makes extensive use of the `keyforkd::test_util` module.
+//! This provides testing infrastructure to set up a temporary Keyfork Daemon. In
+//! your code, you should assume the daemon has already been initialized, whether by another
+//! process, on another terminal, or some other instance. At no point should a program deriving an
+//! "endpoint" key have control over a mnemonic or a seed.
 //!
-//! * Derive Key
+//! ## Server Requests
 //!
-//! ## Extended Private Keys
+//! Keyfork is designed as a client-request/server-response model. The client sends a request, such
+//! as a derivation request, and the server sends its response.  Presently, the Keyfork server
+//! supports the following requests:
 //!
-//! Keyfork doesn't need to be continuously called once a key has been derived. Once an Extended
+//! ### Request: Derive Key
-//! Private Key (often shortened to "XPrv") has been created, further derivations can be performed.
+//!
-//! The tests for this library ensure that all levels of Keyfork derivation beyond the required two
+//! The client creates a derivation path of at least two indices and requests a derived XPrv
-//! will be derived similarly between the server and the client.
+//! (Extended Private Key) from the server.
 //!
-//! # Examples
 //! ```rust
 //! use std::str::FromStr;
 //!
@@ -31,17 +38,121 @@
 //! // use k256::SecretKey as PrivateKey;
 //! // use ed25519_dalek::SigningKey as PrivateKey;
 //!
-//! # let seed = b"funky accordion noises";
+//! #[derive(Debug, thiserror::Error)]
-//! # keyforkd::test_util::run_test(seed, |socket_path| {
+//! enum Error {
-//! # std::env::set_var("KEYFORKD_SOCKET_PATH", socket_path);
+//!     #[error(transparent)]
-//! let derivation_path = DerivationPath::from_str("m/44'/0'").unwrap();
+//!     Path(#[from] keyfork_derive_util::PathError),
-//! let mut client = Client::discover_socket().unwrap();
+//!
-//! let xprv = client.request_xprv::<PrivateKey>(&derivation_path).unwrap();
+//!     #[error(transparent)]
-//! # keyforkd::test_util::Infallible::Ok(())
+//!     Keyforkd(#[from] keyforkd_client::Error),
-//! # }).unwrap();
+//! }
+//!
+//! fn main() -> Result<(), Error> {
+//! #   let seed = b"funky accordion noises";
+//! #   keyforkd::test_util::run_test(seed, |socket_path| {
+//!     let derivation_path = DerivationPath::from_str("m/44'/0'")?;
+//!     let mut client = Client::discover_socket()?;
+//!     let xprv = client.request_xprv::<PrivateKey>(&derivation_path)?;
+//! #   Ok::<_, Error>(())
+//! #   })?;
+//!     Ok(())
+//! }
 //! ```
 //!
-//! In tests, the Keyforkd test_util module and TestPrivateKeys can be used.
+//! ---
+//!
+//! Request objects are typically handled by the Keyfork Client library (such as with
+//! [`Client::request_xprv`]). While unadvised, clients can also attempt to handle their own
+//! requests, using [`Client::request`].
+//!
+//! ## Extended Private Keys
+//!
+//! Keyfork doesn't need to be continuously called once a key has been derived. Once an Extended
+//! Private Key (often shortened to "XPrv") has been created, further derivations can be performed.
+//! The tests for this library ensure that all levels of Keyfork derivation beyond the required two
+//! will be derived similarly between the server and the client.
+//!
+//! ```rust
+//! use std::str::FromStr;
+//!
+//! use keyforkd_client::Client;
+//! use keyfork_derive_util::{DerivationIndex, DerivationPath};
+//! # use keyfork_derive_util::private_key::TestPrivateKey as PrivateKey;
+//! // use k256::SecretKey as PrivateKey;
+//! // use ed25519_dalek::SigningKey as PrivateKey;
+//! # fn check_wallet<T>(_: T) {}
+//!
+//! #[derive(Debug, thiserror::Error)]
+//! enum Error {
+//!     #[error(transparent)]
+//!     Index(#[from] keyfork_derive_util::IndexError),
+//!
+//!     #[error(transparent)]
+//!     Path(#[from] keyfork_derive_util::PathError),
+//!
+//!     #[error(transparent)]
+//!     PrivateKey(#[from] keyfork_derive_util::PrivateKeyError),
+//!
+//!     #[error(transparent)]
+//!     Keyforkd(#[from] keyforkd_client::Error),
+//! }
+//!
+//! fn main() -> Result<(), Error> {
+//!     # let seed = b"funky accordion noises";
+//!     # keyforkd::test_util::run_test(seed, |socket_path| {
+//!     let derivation_path = DerivationPath::from_str("m/44'/0'/0'/0")?;
+//!     let mut client = Client::discover_socket()?;
+//!     let xprv = client.request_xprv::<PrivateKey>(&derivation_path)?;
+//!     // scan first 20 wallets
+//!     for index in 0..20 {
+//!         // use non-hardened derivation
+//!         let new_xprv = xprv.derive_child(&DerivationIndex::new(index, false)?);
+//!         check_wallet(new_xprv)
+//!     }
+//! #   Ok::<_, Error>(())
+//! #   })?;
+//!     Ok(())
+//! }
+//! ```
+//!
+//! ## Testing Infrastructure
+//!
+//! In tests, the `keyforkd::test_util` module and TestPrivateKeys can be used. These provide
+//! useful utilities for writing tests that interact with the Keyfork Server without needing to
+//! manually create the server for the purpose of the test. The `run_test` method can be used to
+//! run a test, which can handle both returning errors and correctly translating panics (though,
+//! the panics definitely won't look tidy).
+//!
+//! ```rust
+//! use std::str::FromStr;
+//!
+//! use keyforkd_client::Client;
+//! use keyfork_derive_util::DerivationPath;
+//! use keyfork_derive_util::private_key::TestPrivateKey as PrivateKey;
+//!
+//! #[derive(Debug, thiserror::Error)]
+//! enum Error {
+//!     #[error(transparent)]
+//!     Path(#[from] keyfork_derive_util::PathError),
+//!
+//!     #[error(transparent)]
+//!     Keyforkd(#[from] keyforkd_client::Error),
+//! }
+//!
+//! fn main() -> Result<(), Error> {
+//!     let seed = b"funky accordion noises";
+//!     keyforkd::test_util::run_test(seed, |socket_path| {
+//!         let derivation_path = DerivationPath::from_str("m/44'/0'")?;
+//!         let mut client = Client::discover_socket()?;
+//!         let xprv = client.request_xprv::<PrivateKey>(&derivation_path)?;
+//!         Ok::<_, Error>(())
+//!     })?;
+//!     Ok(())
+//! }
+//! ```
+//!
+//! If you would rather write tests to panic rather than error, or would rather not deal with error
+//! types, the Panicable type should be used, which will handle the Error type for the closure.
 //!
 //! ```rust
 //! use std::str::FromStr;
@@ -52,11 +163,10 @@
 //!
 //! let seed = b"funky accordion noises";
 //! keyforkd::test_util::run_test(seed, |socket_path| {
-//!     std::env::set_var("KEYFORKD_SOCKET_PATH", socket_path);
 //!     let derivation_path = DerivationPath::from_str("m/44'/0'").unwrap();
 //!     let mut client = Client::discover_socket().unwrap();
 //!     let xprv = client.request_xprv::<PrivateKey>(&derivation_path).unwrap();
-//!     keyforkd::test_util::Infallible::Ok(())
+//!     keyforkd::test_util::Panicable::Ok(())
 //! }).unwrap();
 //! ```
 
@@ -165,10 +275,9 @@ impl Client {
     ///
     /// # let seed = b"funky accordion noises";
     /// # keyforkd::test_util::run_test(seed, |socket_path| {
-    /// # std::env::set_var("KEYFORKD_SOCKET_PATH", socket_path);
+    /// let mut socket = get_socket()?;
-    /// let mut socket = get_socket().unwrap();
     /// let mut client = Client::new(socket);
-    /// # keyforkd::test_util::Infallible::Ok(())
+    /// # Ok::<_, keyforkd_client::Error>(())
     /// # }).unwrap();
     /// ```
     pub fn new(socket: UnixStream) -> Self {
@@ -187,9 +296,8 @@ impl Client {
     ///
     /// # let seed = b"funky accordion noises";
     /// # keyforkd::test_util::run_test(seed, |socket_path| {
-    /// # std::env::set_var("KEYFORKD_SOCKET_PATH", socket_path);
+    /// let mut client = Client::discover_socket()?;
-    /// let mut client = Client::discover_socket().unwrap();
+    /// # Ok::<_, keyforkd_client::Error>(())
-    /// # keyforkd::test_util::Infallible::Ok(())
     /// # }).unwrap();
     /// ```
     pub fn discover_socket() -> Result<Self> {
@@ -217,11 +325,10 @@ impl Client {
     ///
     /// # let seed = b"funky accordion noises";
     /// # keyforkd::test_util::run_test(seed, |socket_path| {
-    /// # std::env::set_var("KEYFORKD_SOCKET_PATH", socket_path);
     /// let derivation_path = DerivationPath::from_str("m/44'/0'").unwrap();
     /// let mut client = Client::discover_socket().unwrap();
     /// let xprv = client.request_xprv::<PrivateKey>(&derivation_path).unwrap();
-    /// # keyforkd::test_util::Infallible::Ok(())
+    /// # keyforkd::test_util::Panicable::Ok(())
     /// # }).unwrap();
     /// ```
     pub fn request_xprv<K>(&mut self, path: &DerivationPath) -> Result<ExtendedPrivateKey<K>>
@@ -244,15 +351,20 @@ impl Client {
             _ => Err(Error::InvalidResponse),
         }
     }
+}
 
+impl Client {
     /// Serialize and send a [`Request`] to the server, awaiting a [`Result<Response>`].
     ///
+    /// This function does not properly assert the association between a request type and a
+    /// response type, and does not perform any serialization of native objects into Request or
+    /// Response types, and should only be used when absolutely necessary.
+    ///
     /// # Errors
     /// An error may be returned if:
     /// * Reading or writing from or to the socket encountered an error.
     /// * Bincode could not serialize the request or deserialize the response.
     /// * An error occurred in Keyforkd.
-    #[doc(hidden)]
     pub fn request(&mut self, req: &Request) -> Result<Response> {
         try_encode_to(&bincode::serialize(&req)?, &mut self.socket)?;
         let resp = try_decode_from(&mut self.socket)?;

crates/daemon/keyforkd-client/src/tests.rs

@@ -1,7 +1,7 @@
 use crate::Client;
 use keyfork_derive_util::{request::*, DerivationPath};
 use keyfork_slip10_test_data::test_data;
-use keyforkd::test_util::{run_test, Infallible};
+use keyforkd::test_util::{run_test, Panicable};
 use std::{os::unix::net::UnixStream, str::FromStr};
 
 #[test]
@@ -109,7 +109,7 @@ fn ed25519_test_suite() {
                     DerivationResponse::try_from(client.request(&req.into()).unwrap()).unwrap();
                 assert_eq!(&response.data, test.private_key.as_slice());
             }
-            Infallible::Ok(())
+            Panicable::Ok(())
         })
         .unwrap();
     }

crates/daemon/keyforkd/src/test_util.rs

@@ -12,20 +12,21 @@ use keyfork_bug::bug;
 #[derive(Debug, thiserror::Error)]
 #[error("This error can never be instantiated")]
 #[doc(hidden)]
-pub struct InfallibleError {
+pub enum UninstantiableError {}
-    protected: (),
-}
 
-/// An infallible result. This type can be used to represent a function that should never error.
+/// A panicable result. This type can be used when a closure chooses to panic instead of
+/// returning an error.  This doesn't necessarily mean a closure _has_ to panic, and its absence
+/// doesn't imply a closure _can't_ panic, but this is a useful utility function for writing tests,
+/// to avoid the necessity of making custom error types.
 ///
 /// ```rust
-/// use keyforkd::test_util::Infallible;
+/// use keyforkd::test_util::Panicable;
 /// let closure = || {
-///     Infallible::Ok(())
+///     Panicable::Ok(())
 /// };
 /// assert!(closure().is_ok());
 /// ```
-pub type Infallible<T> = std::result::Result<T, InfallibleError>;
+pub type Panicable<T> = std::result::Result<T, UninstantiableError>;
 
 /// Run a test making use of a Keyforkd server. The test may use a seed (the first argument) from a
 /// test suite, or (as shown in the example below) a simple seed may be used solely to ensure
@@ -39,6 +40,8 @@ pub type Infallible<T> = std::result::Result<T, InfallibleError>;
 /// runtime.
 ///
 /// # Examples
+/// The test utility provides a socket that can be connected to for deriving keys.
+///
 /// ```rust
 /// use std::os::unix::net::UnixStream;
 /// let seed = b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
@@ -46,6 +49,18 @@ pub type Infallible<T> = std::result::Result<T, InfallibleError>;
 ///     UnixStream::connect(&path).map(|_| ())
 /// }).unwrap();
 /// ```
+///
+/// The `keyforkd-client` crate uses the `KEYFORKD_SOCKET_PATH` variable to determine the default
+/// socket path. The test will export the environment variable so it may be used by default.
+///
+/// ```rust
+/// use std::os::unix::net::UnixStream;
+/// let seed = b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
+/// keyforkd::test_util::run_test(seed.as_slice(), |path| {
+///     assert_eq!(std::env::var_os("KEYFORKD_SOCKET_PATH").unwrap(), path.as_os_str());
+///     UnixStream::connect(&path).map(|_| ())
+/// }).unwrap();
+/// ```
 #[allow(clippy::missing_errors_doc)]
 pub fn run_test<F, E>(seed: &[u8], closure: F) -> Result<(), E>
 where
@@ -82,6 +97,7 @@ where
         rx.recv()
             .await
             .expect(bug!("can't receive server start signal from channel"));
+        std::env::set_var("KEYFORKD_SOCKET_PATH", &socket_path);
         let test_handle = tokio::task::spawn_blocking(move || closure(&socket_path));
 
         let result = test_handle.await;
@@ -89,8 +105,8 @@ where
         result
     });
     if let Err(e) = result {
-        if e.is_panic() {
+        if let Ok(reason) = e.try_into_panic() {
-            std::panic::resume_unwind(e.into_panic());
+            std::panic::resume_unwind(reason);
         }
     }
     Ok(())
@@ -103,6 +119,6 @@ mod tests {
     #[test]
     fn test_run_test() {
         let seed = b"beefbeef";
-        run_test(seed, |_path| Infallible::Ok(())).expect("infallible");
+        run_test(seed, |_path| Panicable::Ok(())).expect("infallible");
     }
 }